Small Molecules and Hematopoietic Stem Cells Presenter: Wang Lan

Introduction Hematopoietic stem cells (HSCs): ▫Multipotent stem cells ▫Residing in the bone marrow ▫Self-renew and differentiate into all blood lineages Aggarwal R, Curr.Mol. Med, 2012, 12(1): 34-49

HSC Location during the Murine Embryonic Development Aggarwal R, Curr.Mol. Med, 2012, 12(1): 34-49

Widely used in transplantation therapies to treat blood disorders of different etiologies The major bottleneck: ▫The difficulty to obtain sufficient HSC numbers ▫Immunologically matched HSCs in the case of allogeneic transplantation

Walasek, MA, Ann. N.Y. Acad. Sci, 2012, 1266: HSC Self-Renewal Regulators

Small molecule drugs: ▫Better understanding of signaling pathways that control cell fate ▫Development of technologies for high-throughput screening ▫Regulation more flexible:  Temporal control the inhibition or activation  Finely tuned by delicately varying the concentrations or combinations Langle D, ACS Chem Biol, 2014, 9(1): 57-71

Small Compounds Screening Approaches Discovery-based chemical screens ▫Probes overall mechanisms ▫No requiring much of prior Knowledge of the targets being modulated Rationale-based chemical approach ▫Hypothesis-driven ▫Using mechanistically known small molecules Li W, ACS Cell Res, 2013, 23: 81-91

Walasek, MA, Ann. N.Y. Acad. Sci, 2012, 1266:

Copper Chelator, TEPA TEPA-supplemented, long-term cytokine cultures significantly increased the number of CD34+CD38- cells and enhanced NOD/SCID repopulating capacity. (Bae B, J.Nut, 1993) TEPA-cultured CB cells were coinfused with uncultured CB cells showed a safety of this approach in a phase I/II clinical trial. ( Peled T, Exp, Hematol, 2004; Peled T, Exp, Hematol, 2005 ) TEPA are under investigation in an ongoing phase II/III study. (Peled T, Cytotherapy, 2004; de Lima, Bone Marrow Transplant, 2008)

HSCs could be modulated through epigenetic regulation Histone Deacetylase Inhibitor, HDACi Valproic Acid Preserve the HSC phenotype for murine and human Chlamydocin Maintain hmPBHSC Trichostatin A Improve maintenance of stem cells in culture Upregulation of cell-intrinsic HSPC fate regulators, such as HoxB4 and AC133 Seet L, Eur. J. Haematol, 2009, 82: ; Araki H, Blood, 2009, 109: ; Milhem M, Blood, 2004, 103: ; Young JC, Cytotherapy, 2004, 6:

Acryl hydrocarbon receptor antagonist Enhances human CD34+ HSC cell amplification Potential mechanism: AhR on the surface of hHSC implicates in pathways regulating hematopoiesis StemRegenin 1, SR1 Boitano AE, Science, 2010, 329(5997):

Other Compounds All-trans Retinoic Acid (ATRA) 6-Bromoindirubin- 3’-Oxime (BIO) Prostaglandin E2 (PGE2) Promote HSC Expansion Regulate HSC Self-renewal Maintenance of HSC stemness Walasek, MA, Ann. N.Y. Acad. Sci, 2012, 1266: